Kids exposed to secondhand smoke have double the risk of hearing loss

Despite years of graphic anti-smoking campaigns and public smoking bans, people continue to light up – especially at home, where more than half of American children and teenagers are exposed to secondhand smoke. Scientists believe that passive smoke either causes or exacerbates lung cancer, asthma, learning disabilities, heart disease and other conditions and now a new study now finds that teenagers exposed to tobacco smoke may also have significant hearing loss – and not even know it. Here is, a brief guide:

How was this study conducted?
Researchers from the New York University School of Medicine tested over 1,500 adolescents aged 12 to 19 for blood levels of cotinine, a byproduct of nicotine that forms when people are exposed to tobacco smoke. They also tested the teens’ ability to hear high-, medium- and low-frequency sounds.

What did the researchers find? Teenagers who’ve been exposed to secondhand smoke have roughly…